The present invention relates to a protective device against the breakage of an inertia wheel.
More precisely, this invention relates to a device which protects an installation from the damage which could be caused by any breakage of an inertia wheel mounted on a rotary machine. This rotary machine could be, for example, a primary pump for a nuclear reactor.
The device to which the invention relates is concerned more particularly with cases where the rotary machine has a horizontal axis and the wheel constitutes a relatively substantial mass. This device is particularly useful when the rotary machine, for example a motor-driven pump set, is placed inside an enclosure which is part of the safety arrangements for the installation as a whole, as is the case with nuclear plants for producing electrical energy.
Still more precisely, the device prevents fragments of the inertia wheel from flying off and thus becoming a projectile which could damage the confinement enclosure.
The hypotheses taken into consideration are as follows:
the speed of rotation of the wheel is equal to the nominal speed of rotation;
only cases where a quarter of the wheel flies off are taken into consideration; and
the possibility of the kinetic energy of rotation being converted into kinetic energy of translation during accidental breakage of the wheel is taken into account.